The invention relates to a bipolar electrode that can be implanted having a cathode, located at its distal end and carried by a shaft or a tube, and an anode spaced apart therefrom, with the electrode having an anchor at the distal end for fastening in the tissue of a heart, with the bipolar electrode being formed from two unipolar electrodes, one of which is provided with the cathode or the anchor or anchors at its distal end and the other one of which is provided with the anode at a second shaft or tube, with the second shaft accepting the first shaft provided with the cathode and being adjustable or displaceable in reference thereto in the axial direction and with the cathode and the anode each being electrically connected to a bipolar plug at least in the operational position.
Such a bipolar electrode is known from U.S. 2006/064159 A 1. Here, prongs or bendable pins are provided as anchors at the anode connected to the second shaft, located at the exterior, which can only become effective when the head of said shaft can be inserted sufficiently deep into the tissue. Such barbed pins can cause collisions or interlocking, primarily when passing through the nitral cap. If the anchor at the distal end of the cathode was embodied as a helical electrode or helical screw, the wall of the tissue or tissues through which the electrodes must be pushed towards the heart could be injured.
Pacemaker electrodes with helical screws serving for anchoring are known, for example from U.S. Pat. No. 5,716,390, which during implantation are retracted in the tube of the electrode and can be axially displaced in the heart with the aid of a special mechanism for the anchoring process to be performed, however this requires considerable expenses. Possible interlocking with pin-shaped or barb-like anchors has been tolerated in the past.